Field of the Invention
This invention pertains to the cutting of sheets or films made of one or several layers of plastic material, especially the cutting of transparent or translucent sheets which are suitable for use in the production of compound panes. More specifically, the invention pertains to a device for cutting these sheets, temporarily or permanently assembled with other elements of the pane, by a routing operation.
Related Art
In the production of compound panes, especially safety panes made of two sheets of glass and an intermediary sheet or layer of plastic material, for example, one made of polyvinylbutyral or polyurethane, the constituent elements of the pane are assenbled by the stacking of the elements, followed by a calendering done by passing the stacked formation between press rollers, and a pressure sealing cycle.
When the elements are being stacked, the intermediary sheet of plastic material is in the form of a preform, which is generally horizontal trapezoidal, the size of which is slightly larger than that of the pane.
After the stacking, and before the calendering operations, the parts of the intermediary sheet which protrude from the edges of the pane are cut manually by routing with a metal blade, with the worker performing this routing operation keeping the blade prssed against the edge of the pane. This operation involves long and costly labor. In addition, this method can sometimes be imprecise, thus requiring the trimming of the parts of the intermediary layer still protruding from the pane, generally after the pressure sealing cycle. Another problem involved in this manual cutting is that the tool can damage areas along the edges of the glass sheets, thus embrittling the pane. Finally, the blades used tend to wear quickly and must be changed often.
Automatic cutting devices have already been described, for example in French patent publication No. 2,510,029.